From b9567720a1b8e739380e0241413606c056c57859 Mon Sep 17 00:00:00 2001 From: Steve Capper Date: Thu, 6 Dec 2018 22:50:42 +0000 Subject: arm64: mm: Allow forcing all userspace addresses to 52-bit On arm64 52-bit VAs are provided to userspace when a hint is supplied to mmap. This helps maintain compatibility with software that expects at most 48-bit VAs to be returned. In order to help identify software that has 48-bit VA assumptions, this patch allows one to compile a kernel where 52-bit VAs are returned by default on HW that supports it. This feature is intended to be for development systems only. Signed-off-by: Steve Capper Acked-by: Catalin Marinas Signed-off-by: Will Deacon --- arch/arm64/include/asm/elf.h | 4 ++++ 1 file changed, 4 insertions(+) (limited to 'arch/arm64/include/asm/elf.h') diff --git a/arch/arm64/include/asm/elf.h b/arch/arm64/include/asm/elf.h index bc9bd9e77d9d..6adc1a90e7e6 100644 --- a/arch/arm64/include/asm/elf.h +++ b/arch/arm64/include/asm/elf.h @@ -117,7 +117,11 @@ * 64-bit, this is above 4GB to leave the entire 32-bit address * space open for things that want to use the area for 32-bit pointers. */ +#ifdef CONFIG_ARM64_FORCE_52BIT +#define ELF_ET_DYN_BASE (2 * TASK_SIZE_64 / 3) +#else #define ELF_ET_DYN_BASE (2 * DEFAULT_MAP_WINDOW_64 / 3) +#endif /* CONFIG_ARM64_FORCE_52BIT */ #ifndef __ASSEMBLY__ -- cgit v1.2.3